The invention applies particularly, but not exclusively, within the field of spectacles devoid of lens-holding rims, otherwise known by the term “rimless”, in which mount members of different configuration are fixed directly to the lens of the spectacles. The term “mount member” is intended to include in the present context, for example, the articulation lugs for the arms of the spectacles or the nasal support bridge, extending to connect the lenses centrally.
In a first example of known fixing devices, provision is made for the lens to be fixed to the mount member by the insertion and locking of a pin-type appendage protruding from the mount member into a through hole provided in the lens, subject to a bush member being received in the hole and arranged so as to be interposed, when assembly has taken place, between the pin and the lens. The interposition of the bush member, typically made of plastics material, makes it possible to obtain adequate and stable coupling and also a greater and more uniform distribution of the clamping stresses between the surfaces of the mutually coupled lens and pin, especially in the presence of materials, such as those of the lens and the frame, having different mechanical characteristics. A solution of the aforesaid type is described in International Application WO 03/060595.
In a second example of known devices, provision is made for the mount member to comprise a pair of pin-type appendages standing up in the same direction from the aforesaid member and capable of engaging a respective pair of bush members, subject to these latter being received in corresponding holes passing through the lens. The provision in close position of the pair of appendages ensures the locking between the mount member and the lens, opposing any relative rotational movements in the use of the spectacles owing to possible accidental slackening of the locking forces between the pins and bushes. An example of a device having the aforesaid characteristics is known from US Patent Application No. 2005/0128429. According to this technical solution, provision is made for the pins to be equipped with annular projections, having a pointed configuration in cross-section, and capable of impinging on the inner surface of the bush for mutual coupling in order to guarantee, by means of localised deformation of the bush itself, the relative locking with same.